The invention relates to a nuclear magnetic resonance apparatus having a main magnet system for producing a uniform steady main magnetic field in an examination space and an acoustic communication system between the examination space and the environment.
In "Radiology", Volume 149, No. 3, p. 855 there is described a communication system for use in medical nuclear magnetic resonance examination. The system described therein is provided with a pair of bellows by means of which acoustic information can be transmitted through a pipe via air-pressure displacements. Such a system has disadvantages, such as the necessity for the patient to be able to operate the bellows, the communication is comparatively poor in information and acts in one direction, the positioning of the bellows and further components of the system, etc.
The problem for a communication system in a nuclear magnetic resonance apparatus is that the magnetic field in the examination space must not be disturbed thereby. With the use of a conventional loudspeaker, this will be the case, however.